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2014
Conference Paper
Title
High-rate deposition of SI absorber layers by electron beam evaporation and first electron beam crystallization tests
Abstract
In earlier electron beam physical vapor deposition tests (EB-PVD), using a conventional copper crucible (A), high Si deposition rates at relatively high EB power together with a contamination level of 1016 cm-3 are demonstrated. To improve the rate vs. EB power relation as well as the Si layer purity, two alternative high rate EBPVD methods are investigated and reported here - a contact-less crucible setup (B) and a crucible-free setup (C).In these experiments comparable deposition rates of ~ 70 nm/s are demonstrated for (B) and (C) too, but at an improved rate vs. EB power relation. Critical factors of the methods (B) and (C) are the risk of melt contact to the crucible bottom by soaking through the Si nugget bed for (B) and the heat up process to evaporation conditions for(C) together with the control of the melt area on the top surface of the high-purity single crystal rod, which was used as evaporation source. To demonstrate the overall quality of 7 mm amorphous Si films, deposited by the crucible-free EB-PVD onto a (100) Si substrate, they were crystallized by an area scanning EB process, resulting in a single crystal Si film area with orientation, identically to the substrate.
Author(s)